Cardiovascular Diseases
Diseases

Alcohol and Cardiovascular Disease

Alcohol is a commonly used drug worldwide. Epidemiological studies have identified alcohol consumption as a factor that may either positively or negatively influence many diseases including cardiovascular disease. Often there seems to be a differential effect of various drinking patterns, with frequent moderate consumption of alcohol being salutary and binge drinking or chronic abuse being deleterious to one’s health.
Epidemiologic studies that examine patterns of health and disease and associated factors in a population, point to a complex association between alcohol consumption and cardiovascular disease. With few exceptions, studies from several countries demonstrate a 20–40% lower cardiovascular disease incidence among drinkers of alcoholic beverages compared with non-drinkers. The general consensus currently is that compared with abstinence, frequent moderate consumption of alcohol is associated with the lowest risk for coronary heart disease incidence and mortality.
For example, 1–2 drinks per day is a negative risk factor for atherosclerosis and its clinical sequelae myocardial infarction and ischemic stroke.
On the other hand binge or heavy episodic drinking, defined in the USA as consuming 5 or more drinks in a relatively short time period, is associated with increased cardiovascular disease and associated mortality.
In terms of beverage choice, some studies support a preferential red wine protective effect, attributable to both the alcohol (ethanol) and the polyphenolic antioxidant content, in particular resveratrol.

Alcohol and coronary heart disease: a meta-analysis. (2002)
Association of alcohol consumption with selected cardiovascular disease outcomes: a systematic review and meta-analysis. (2011)
Roles of drinking pattern and type of alcohol consumed in coronary heart disease in men. (2003)
Differential effects of polyphenols and alcohol of red wine on the expression of adhesion molecules and inflammatory cytokines related to atherosclerosis: a randomized clinical trial. (2012)

Atherosclerosis

Atherosclerosis , a chronic inflammatory condition in which the artery wall thickens as a result of the accumulation of cholesterol, macrophages and smooth muscle cells (SMC), ultimately restricting blood flow through the artery, is the main pathologic condition underlying coronary artery and cerebrovascular disease leading to heart attack and stroke, respectively. In the pathogenesis of atherosclerosis, increases in plasma low density lipoprotein (LDL) leads to a proportional increase in the entry of cholesterol laden LDL particles into the arterial wall across a “compromised” endothelial monolayer, where it accumulates. Once there, it can become oxidized, possibly by free radical production from adjacent endothelium, smooth muscle cells or an isolated macrophage. Oxidized LDL has numerous effects on a variety of cells, many of which are believed to cumulatively exacerbate atherothrombosis. These include promotion of monocyte adhesion and infiltration to the intima by causing production of monocyte chemotactic protein-1 (MCP-1) by endothelium and expression by endothelium of monocyte-binding proteins including intercellular adhesion molecule-1 (ICAM-1), foam cell formation following uptake of oxidized LDL via scavenger receptors (SR-A type I and II and CD36), and stimulation of the migration of medial SMC into the intima where they proliferate in response to growth factors such as platelet derived growth factor (PDGF). In the intima, SMC produce extracellular matrix molecules including collagen and elastin. The most common clinical complication of atherosclerosis occurs upon plaque rupture which allows blood components to come into contact with plaque lipids and tissue factor, resulting in thrombus formation.

Oxidized LDL, LOX-1 and atherosclerosis. (2011)

Alcohol and Nitric Oxide (NO)

Nitric oxide (NO) is a key regulatory signaling molecule in the vasculature. It is synthesized by the heme-containing, calcium and calmodulin-dependent enzyme nitric oxide synthase in endothelial cells (eNOS) from L-arginine in a reaction that produces stoichiometric amounts of L-citrulline. Activation of NOS and release of NO results in stimulation of a soluble guanylyl cyclase leading to a profound increase in intracellular cyclic guanosine monophosphate (cGMP) levels within most target cells. NO has a wide range of actions important in maintaining vascular homeostasis. In addition to causing vasodilation, it has antiproliferative, antioxidant and anti-inflammatory properties that inhibit atherogenesis. Common risk factors for atherosclerosis such as hypercholesterolemia, hypertension, smoking and diabetes mellitus are associated with reduced NO in the arterial wall. Because of these findings, numerous therapies have been investigated based on enhancing NO release, thereby reversing endothelial dysfunction and preventing atherogenesis.
Researchers have wondered whether moderate alcohol consumption mediates some of its cardioprotective effects by stimulating NO, and conversely, whether binge drinking diminishes NO availability. Moderate alcohol consumption increased the expression of eNOS protein in the vasculature and NO metabolites in the blood.
Chronic ethanol ingestion increased NO release from pulmonary endothelial cells by a mechanism involving phosphatidylinositol 3-kinase (PI3K)-mediated increases in eNOS expression and increases in protein-protein interactions between eNOS and hsp90.

Ethanol increases endothelial nitric oxide production through modulation of nitric oxide synthase expression. (1999)
Evidence of cardiovascular protection by moderate alcohol: Role of nitric oxide. (2005)

Endothelial Progenitor Cells

Evidence indicates that the injured endothelial monolayer may be regenerated by circulating bone marrow-derived endothelial progenitor cells (EPC), which accelerate re-endothelialization and protect against the initiation and progression of atherosclerosis. Higher circulating levels of progenitor cells reflect greater repair capacity and have been shown to reduce the progression of atherosclerosis. It is suggested that alcohol consumption may increase the number of circulating EPC. Moderate red wine consumption improved neovascularization and blood flow recovery after ischemia in hypercholesterolemic mice and had a positive effect on EPC number and functional activity. It is shown a modulatory effect of ethanol and polyphenols on EPC that is anti-atherogenic.

Endothelial progenitor cell therapy in atherosclerosis: a double-edged sword? (2009)
Moderate consumption of red wine (cabernet sauvignon) improves ischemia-induced neovascularization in ApoE-deficient mice: effect on endothelial progenitor cells and nitric oxide. (2007)

Alcohol and Reactive Oxygen Species (ROS).

Increased production of reactive oxygen species (ROS) contributes to mechanisms of vascular/endothelial dysfunction and atherosclerosis. Oxidative stress is mainly caused by an imbalance between the activity of endogenous pro-oxidative enzymes (such as NADPH oxidase, xanthine oxidase, or the mitochondrial respiratory chain) and anti-oxidative enzymes (such as superoxide dismutase, glutathione peroxidase, and heme oxygenase) in favor of the former. ROS may play a role in mediating alcohol’s various effects, particularly in relation to its vasorelaxant effect and its protective effect against ischemia reperfusion injury.
Oxidative stress induced by ROS plays an important role in the pathogenesis of ischemia/reperfusion injury. The regular moderate consumption of alcoholic beverages is believed to protect against ischemia-induced myocardial injury by affecting the prooxidant/antioxidant balance.

Moderate ethanol ingestion and cardiovascular protection: from epidemiologic associations to cellular mechanisms. (2012)

Monocyte Chemotactic Protein-1

Monocyte chemotactic protein-1 (MCP-1) plays an important role in the recruitment and activation of monocytes and thus in the development of atherosclerosis. In response to several atherogenic stimulants such as oxidized LDL, platelet derived growth factor (PDGF) and interleukin-1β (IL-1β), MCP-1 is induced in endothelial cells, smooth muscle cells and monocytes. MCP-1 mediates its biological activity mainly through interaction with an MCP-1 receptor, CCR2, (also known as C-C chemokine receptor) on the surface of its target cells which include monocytes. This receptor belongs to the superfamily of G protein-coupled receptors with seven transmembrane domains. The important role of CCR2 in atherogenesis has been demonstrated in studies using gene knockout animal models; there was a marked decrease in atherosclerotic lesion formation in apo-E-null mice that lacked CCR2 and increased CCR2 expression is evident in patients with hypercholesterolemia. Ethanol inhibits IL-1β-stimulated endothelial MCP-1 expression by decreasing MCP-1 mRNA stability, binding of the transcription factors nuclear factor kappa B (NF-κB) and activator protein-1 (AP-1), and MCP-1 gene transcription. These data suggest a possible mechanism whereby ethanol could block monocyte adhesion and subsequent recruitment to the sub endothelial space and thus inhibit atherogenesis. Furthermore, it has found that only beverages with the highest polyphenol content (e.g., red wine) inhibited plasma MCP-1 concentrations. Taken together, these studies support an effect of both ethanol and polyphenols in modulating MCP-1 expression.

Ethanol inhibits monocyte chemotactic protein-1 expression in interleukin-1{beta}-activated human endothelial cells. (2005)
Ethanol beverages containing polyphenols decrease nuclear factor kappa-B activation in mononuclear cells and circulating MCP-1 concentrations in healthy volunteers during a fat-enriched diet. (2007)

Smooth Muscle Cell (SMC) Differentiation/Phenotypic Switching and Vascular Disease

Vascular smooth muscle cell (VSMC) proliferation contributes to the development of atherosclerosis. Red wine consumption due to the polyphenol content has been reported to counteract atherosclerosis progression possibly through inhibition of VSMC proliferation, among other mechanisms. Four major polyphenols from wine (resveratrol, quercetin, ethyl gallate, and catechin) inhibited serum-induced VSMC proliferation when applied as a single treatment. Furthermore, optimized equipotent mixture showed enhanced synergy inhibiting VSMC proliferation.

Synergy study of the inhibitory potential of red wine polyphenols on vascular smooth muscle cell proliferation. (2012)

Conclusions

Many epidemiologic studies demonstrate a complex association between alcohol consumption and cardiovascular disease, with frequent low-moderate consumption being protective and chronic abuse or binge drinking being exacerbatory.
Alcohol’s impact on cardiovascular disease is, therefore, likely the cumulative result of several separate effects.

USE OF SALVIA MILTIORRHIZA EXTRACTS IN TREATMENTS FOR

CARDIOVASCULAR DISEASES

Salvia miltiorrhiza Bunge (Danshen) belongs to the Labiatae family of the plant kingdom. It is considered to have the function of activating blood circulation and removing blood stasis, entering the “heart”, “pericardium”, and “liver” channels according to the theory of traditional Chinese medicine (TCM). Danshen has been widely used in oriental countries, especially China, to treat various circulatory disturbance-related diseases for its special pharmacological actions, including vasodilatation, anticoagulation, antiinflammation, and free radical scavenging. In recent years, traditional medicines have been playing more and more important roles in the maintenance of health, the prevention and treatment of diseases, as well as plant-based drug discovery .
There are two main active compounds:

• the hydrophilic: salvianolic acid A and B (which contain poliphenolic structures), danshensu, protocatechuic aldehyde, and protocatechuic acid).

• the lipophilic: Tanshinone I, IIA, IIB; Tanshinone IIA (Tan IIA), which is a member of the major lipophilic components extracted from Salvia miltiorrhiza Bunge, has indicated significant therapeutic effects on various diseases in vivo and in vitro. Since Tan IIA is not easy to be absorbed through intestinal pathway, sodium tanshinone IIA sulfonate (STS) was developed to raise the bioavailability.
  
  

• Vasodilative Effect Tan IIA produced a concentration-dependent relaxation in isolated spontaneously hypertensive rat (SHR) aortic rings precontracted through ATP-sensitive K(+) channel to lower [Ca(2+)]. Endothelium denudation, inhibition of nitric oxide synthase (NOS), inhibition of the cytochrome P450 epoxygenase, and blockade of the large conductance Ca(2+)-activated potassium channels (BKca) significantly decreased the vasodilation elicited by Tan IIA, which indicated that Tan IIA induces an endothelium-dependent vasodilation in coronary arterioles; nitric oxide (NO) and cytochrome P450 metabolites contribute to the vasodilation. Tan IIA prevented the hypertension-induced reduction of endothelial NOS (eNOS) and increased eNOS expression to levels higher than sham-operated control. The results also indicated that eNOS stimulation was one mechanism by which Tan IIA induced vasodilation and reduces blood pressure.
  • Tan IIA action on Estrogen Receptors Because our recent study identified Tan IIA as a new member of the phytoestrogens, we hypothesized that its action might be mediated by estrogen receptor (ER) in vascular endothelial cells. The effect of Tan IIA on blood vessels was investigated by vascular ring assay using endothelium-intact and endothelium-denuded rat aortas. Similar to estrogen, Tan IIA caused an nitric oxide- and endothelium-dependent relaxation, which was blocked by ER antagonist ICI 182,780. We demonstrate that Tan IIA is capable of activating the estrogen receptor signal pathway, leading to increased endothelial nitric oxide synthase gene expression, nitric oxide production, ERK1/2 phosphorylation, and Ca mobilization. Collectively, these effects contribute to Tan IIA's vasodilative activity effects. Novel phytoestrogens can be developed as an alternative hormone replacement therapy for safer and more effective treatment of cardiovascular diseases.
    (”Direct vasorelaxation by a novel phytoestrogen tanshinone IIA is mediated by nongenomic actionof estrogen receptor through endothelial nitric oxide synthase activation and calcium mobilization. 2011”)

• Inhibition of Left Ventricular Hypertrophy Tan IIA could inhibit left ventricular hypertrophy (LVH) with different mechanisms.
  • Overwhelming postloading is a main factor promoting LVH, therefore controlling hypertension is very important in LVH inhibition. Tan IIA has shown vasodilatation effect through adenosine triphosphate (ATP)-sensitive K(+) channel to lower the concentration of Ca2+ in myocytes, regulate the condition of hypertension, and inhibit the formation of hypertrophy .
  • Tan IIA could also prevent LVH through inhibiting angiotensin receptor (ATR) expression or blocking free Ca2+ influx in rats with hypertrophic myocardium caused by abdominal aorta constriction.
  • Additionally, Tan IIA has been reported to block the transforming growth factor (TGF) beta1/Smads signal pathway and inhibit the formation of myocardial hypertrophy.
  • Furthermore, Tan IIA depressed the intracellular generation of reactive oxygen species (ROS), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, and subunit p47 (phox) expression, which are the factors inducing LVH.
  • Tan IIA conferred its beneficial effects on the collagen metabolism probably through its regulation of transcript levels of the MMPs/tissue inhibitor of metalloproteinases (TIMPs) balance.
  • Tan IIA could prevent LVH induced by Ang II, which might be related to its inhibition of proto-oncogene c-fos expression. Tan IIA had the definite function in preventing LVH by its action on the protein kinase B (PKB/Akt) signaling pathway, which could regulate the expression of proto-oncogene c-fos.

• Attenuation of Atherosclerosis In addition to VSMC proliferation and intimal hyperplasia, injury of vascular endothelium, lipid deposition, oxidative stress, and inflammatory reaction also play important roles in the formation and progression of atherosclerosis. Endothelial cells can secrete two kinds of substances with opposite functions: one can induce VSMC apoptosis (such as NO), and the other can inhibit VSMC apoptosis (such as endothelin-1 (ET-1), Ang II, and growth factors). Unbalance between them decides whether endothelium is injured. NO is the key factor in signal transduction, it can relax blood vessels and activate genes relative to VSMC apoptosis. Tan IIA could inhibit the negative effect of Ang II on NO production and eNOS expression in porcine aortic endothelial cells. Another in vitro study showed that Tan II might inhibit cell apoptosis, inducing protective effect on vessel endothelium . Tan IIA could also reduce plaque area in endothelium, decrease lipid deposition, and significantly inhibit the formation of atherosclerosis, although the level of total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) in serum had not been changed by Tan IIA.

• Inhibitory Effect on the Inflammatory Responses Inflammatory effect can induce endothelium injury, foam-cell appearance, and leukocytes adhesion, all of which play important roles in the formation of atherosclerosis. At least two studies had verified that Tan IIA could decrease inflammatory effect and attenuate atherosclerosis of vessels. That expression reduction of CD40 and MMP-2 activity might be the potential mechanisms of antiatherosclerosis effect of Tan IIA. Tan IIA could dose-dependently inhibit atherosclerotic lesion through downregulation of protein expression and activities of MMP-2 and MMP-9 as well as serum VCAM-1 and interleukin (IL)-1β in rabbits fed high-fat diet.

• Antioxidant Effect Oxidation reaction was involved in various pathological mechanisms, inducing different diseases including MI, angina pectoris, and restenosis after PCI, LVH, and so on. Tan IIA can inhibit these reactions, which have been mentioned in the above experiments . To test the hypothesis that Tan IIA can alter the expression and/or activity of specific antioxidant enzymes to prevent cells from oxidant damage, at least three experiments were conducted and demonstrated that the cell protective effect of Tan IIA was mediated primarily by induction of glutathione peroxidase (GPx) gene expression and activity, as well as other antioxidant enzyme activities in the heart.
  • Tan IIA could scavenge the free radicals produced in the superoxide approach, which might be one of the important mechanisms in myocardiocyte damage.
  • Other studies suggested that Tan IIA significantly attenuates myocardiocyte or vasculocyte damage, which might be attributed to its inhibition of ox-LDL production. Increasing of Cu/Zn SOD activity as well as mRNA and protein expression by Tan IIA might protect LDL against oxidation induced by superoxide anion in vessel. Active oxygen free radical is a major factor inducing endothelial injury; hydrogen peroxide can promote the formation of free radicals, which can penetrate cell membrane, combine with Fe2+ or Cu2+, induce lipid peroxidation, and lead to endothelium injury and formation of atherosclerosis finally.

• Antiplatelet, Anticoagulant, and Antithrombotic Effect Tan IIA can:
  • decrease the blood viscosity obviously;
  • inhibit the activation of thrombin;
  • promote fibrin degradation;
  • it can inhibit the function of platelets and the formation of thrombus. Tan IIA could significantly decrease the platelet number, with efficacy similar to aspirin, by inhibiting P-selectin expression in a concentration-dependent manner. Tan IIA could inhibit the thrombus formation and platelet aggression in in vivo study, and it exerted more significant effect on antiplatelet than anticoagulation.
  • CD41 and CD62p are two of the most important inflammatory factors, which can induce platelets aggregation and promote blood coagulation. Tan IIA could decrease the expression of CD41 and CD62p, which might inhibit platelet aggregation and blood coagulation.

• Antimyocardial Hypoxia Tan IIA could decrease LVEDP and heart volume and reduce myocardial oxygen consumption. Various studies have suggested that Tan IIA might dilate coronary artery, inhibit vascular contraction, increase coronary blood flow and reduce oxygen consumption of myocardiocytes with different mechanisms. Tan IIA could decrease intracellular calcium overload and K+ outflow, inhibit Na+ inflow, keep the balance of membrane potential, and therefore protect myocardiocyte in hypoxia.

• Reduction of Myocardial Infarct Size Tan IIA can dilate coronary artery and increase coronary blood flow, which is beneficial for reducing MI size. Various experiments have demonstrated that Tan IIA might recover cardiac function and reduce MI size significantly with different mechanisms.
  • The possible mechanism responsible for the effect of Tan IIA was associated with the phosphatidylinositol 3-kinase (PI3K/Akt)-dependent pathway, which was accompanied with decreased cardiac apoptosis and inflammation.
  • In addition, Tan IIA could reduce MI size through prolonging survival of endothelial cells .
  • Tan IIA could reduce MI size and myocardial ischemia injury through promoting angiogenesis and upregulating vascular endothelial growth factor (VEGF) expression. Tan IIA might establish extensive collateral circulation and increase blood flow in ischemic area.

• Inhibiting Ischemia Reperfusion Injury Ischemia reperfusion (IR) exerts disturbance of microcirculation and leads to many diseases, including myocardial stunning and reperfusion arrhythmia. Production of oxygen free radicals, calcium overload in myocytes, endothelial cell injury, adhesion of leukocyte, energy supply reduction, mitochondrial damage, and myocardiocytes apoptosis are considered to be involved in this process. Tan IIA can inhibit the activation of proteases and ameliorate calcium overload in myocytes.. In addition, Tan IIA can increase the SOD content in the injured myocytes, decrease the MDA concentration, and influence electron transfer reaction in mitochondria, thus scavenge the free acids, reduce the lipid peroxidation, and protect myocytes and vascular endothelial cells in the IR process. ET, which can induce constriction of the vessel, increases significantly in IR, and Tan IIA can inhibit the production and release of ET, promote secretion of NO, and decrease IR injury of the heart.
  ”Tanshinone IIA: A Promising Natural Cardioprotective Agent. 2011”

• Ros Scavengers During Cardiovascular Injury Due to their polyphenolic structure, salvianolic acids are thought to be free radical scavengers. Indeed, both Sal B and Sal A show their high radical scavenging capacity measured by neutralizing free radicals assays.
  Seven phenolic compounds isolated from S. miltiorrhiza inhibited lipid peroxidation of rat liver microsomes induced by iron/cysteine and vitamin C/NADPH and the hemolysis of rat erythrocytes induced by H2O2 in vitro. It was found that Sal A was the most potent antioxidant among the salvianolic acids. However, Sal B was thought to have much more commercial value for the food and medicine purposes due to the containment of the highest amounts in S. Miltiorrhiza. Sal B exhibited higher scavenging activities than vitamin C against HO•, O2•-. However, their iron chelating and H2O2 scavenging activities were lower than vitamin C .
  Salvianolic acids were not only demonstrated to have antioxidant activity in vitro, but also been proven to act as cardiovascular protectors in vivo. Using ischemia-reperfusion injury model of an isolated rat heart, it was demonstrated that Sal A lowered the ventricular fibrillation rate, decreased cellular LDH leaking and reduced lipid peroxidation in damaged cardiac tissue. Feeding with 5% water-soluble extract of S miltiorrhiza which contained Sal B significantly lowered plasma cholesterol level, reduced endothelial damage and the severity of atherosclerosis in diet-induced hypercholesteremic rabbits. The cardiovascular protection potential of Sal B was contributed by its ROS scavenging ability. Sal B-treated LDL exhibited vitamin E-binding ability and was resistant to Cu2+-induced oxidation . Moreover, intravenous administration of Sal A (0.3-3 mg/kg) significantly attenuated myocardial injury and improved mitochondrial respiratory function in rat with isoproterenol-induced myocardial infarction .
  Recently, salvianolic acids were found to inhibit the proliferation of rat aortic smooth muscle cells stimulated by homocysteine, an oxidative stress factor. Apart from what have been mentioned above, salvianolic acids have been reported to protect cardiomyocytes from drug-induced toxicity due to its ROS scavenging ability.

• Inhibition of Leukocyte-Endothelial Cell Adherence
  Leukocyte attachment, migration as well as adhesion molecule expression on arterial endothelial cells all are important steps in the development of early atherosclerosis. A series of studies on salvianolic acids regulating leukocyte-endothelial cell adherence have been undertaken. It is well-established that endothelial-leukocyte adhesion molecules on aortic endothelial cells can be induced by TNF-α. Sal B was found to attenuate VCAM-1 and ICAM-1, but not E-selectin expression, in a dose-dependent manner (1-20 μg/ml). These effects were associated with its anti-inflammatory property through inhibiting the activation of NFkB pathway triggered by TNF-α.

• Inhibition of Inflammation And Regulation of Metalloproteinaseses Expression During Cardiovascular Injury
  Synthesis and release of inflammatory cytokines from vascular smooth muscle cells is an important contributor to the pathogenesis of atherosclerosis. Genetic expression of COX-2 and protein expression of MMP-2 and MMP-9 in LPS-treated HASMCs could be inhibited by Sal B via the suppression of ERK1/2 and JNK phosphorylation, reduction of PGE2 production and NADPH oxidase activity. Sal B not only inhibited MMP-2 activation induced by LPS, but also inhibited MMP-2 activation induced by TNF-α, angiotension II and H2O2. It has been demonstrated that Sal B inhibited TNF-α, angiotension II and H2O2-induced MMP-2 mRNA, protein expression, and gelatinolytic activity in a concentration-dependent manner (0.1-10 μM), which was through the inhibition of NADPH oxidase-dependent ROS generation .
  In experimental myocardial infarction in rat, the administration of salvianolic acids significantly decreased infarct size, improved left ventricular function and decreased myocardial malondialdehyde levels compared with the control group. The cardioprotection of salvianolic acids against infarct-induced left ventricle remodeling was significantly contributed by the down-regulation of MMP-9 mRNA expression level and its activity at the infarct area.

• Regulation of Kinase Activity and Potential Immunomodulation
  Salvianolic acids regulate intracellular kinase-associated signaling pathway , indicating that salvianolic acids interact with phosphotyrosine or phosphoserine/threonine-binding domain. Sal A and Sal B were inhibitors of the protein-protein interaction mediated by SH2 domains of Src-family kinases Src and Lck.
  ”Salvianolic acids: small compounds with multiple mechanisms for cardiovascular protection. 2011”

Conclusions
Such unique properties make salvianolic acids and Tanshinone IIA excellent candidates for future development of cardiovascular protective agents.